Recently, the technologies in the field of electric and electro industries have developed, and the technology of devices that can promptly process a lot of data has been rapidly developed.
An information processing device processes inputted-by-observer data and generates result data with very fast calculating speed.
However, in spite of the usefulness of this information processing device, observers can't read and understand the result data generated from the information processing device, with only the information processing device, because the result data computed and processed are processed and stored in the information processing device as a status of an electrical signal.
For this reason, a display device, which observers can read and understand the result data generated from the information processing device through, is necessary as a interface device.
A cathode ray tube (CRT) type display device and a liquid crystal display (LCD) device are representative as the above-mentioned display device.
The CRT type display device scans electrons to a screen on which fluorescent materials and color pixels are distributed, and displays designed images. The scanned electrons are discharged from an electron gun and electro-magnetically controlled in the CRT type display device.
The LCD (Liquid Crystal Display device) makes the light, the transmissivity of which is altered by liquid crystal, to pass a color filter and to displays designed images.
The LCD can display an equivalent quality of images compared with the CRT type display device, but the LCD is small-sized and lightweight since it display the images by a several-micrometer (μm) thickness of liquid crystal layer.
Since the LCD cannot radiate light by itself, the LCD needs another light source.
For this reason, the LCD is divided into a reflective type LCD, a transmissive type LCD and a transmissive and reflective type LCD.
The reflective type LCD displays images using an external light, such as sunshine, interior illumination and outdoor illumination, etc.
The transmissive type LCD displays images using light generated by consuming internally charged electric power.
In this case, the reflective type LCD has an advantage that the power dissipation is very low because the reflective type LCD needs not consume electric power for lightening, but has a disadvantage that it can't display images where light does not exist or is weak because the display of information is possible only where light exists.
The transmissive type LCD has an advantage that it can provide a good quality of display anywhere whatever external light exists, but has a disadvantage that the power dissipation is higher than that of the reflective type LCD, because it uses the light generated by the consumption of electric power.
The reflective and transmissive type LCD has the advantages of the reflective type LCD and the transmissive type LCD together. Namely, the reflective and transmissive type LCD displays images using light generated by the consumption of electric power in a dark place, and displays images using external light in a well-lighted place. So, the reflective and transmissive type LCD can minimize the power dissipation for display.
However, the reflective type and the reflective and transmissive type LCD specially have a disadvantage that they can't satisfy the various requirements from the observers, since the viewing angle of them is fixed when being manufactured.